Defence Forces members, their families and retired military personnel are expected to vote en masse against Fine Gael in both the local and European elections.
The Irish Examiner has learnt that already many soldiers, sailors and air crews have used their postal votes to vote against Fine Gael candidates.
Their families and retired members of the Defence Forces are likely to follow suit on Friday when polling gets underway around the country.
A major campaign has been launched on social media against the Government in recent weeks by a number of groups associated with military personnel, including those who organised two protest marches in Dublin and Cork to highlight the near-poverty being endured by military families.
They have been angered that the Government hasn't moved to improve pay and conditions for Defence Forces personnel, who are the poorest paid public servants.
There were hopes that the Public Service Pay Commission (PSPC) would recommend substantial increases in allowances for Defence Forces personnel, especially in the run-up to the elections.
There were noises from Government circles that an announcement would be made this week, but following leaks about the PSPC recommendations nothing has emerged from the Government.
A number of serving Defence Forces members told the Irish Examiner that their colleagues, across the ranks, had been talking openly about how they used their voting right to send a distinct message to Government and that would be repeated if they failed to improve military pay and conditions before the next General Election.
"If they (the Government) want to pull a rabbit out of the hat now it's too late. We have voted. If anything, the leaks from the Public Service Pay Commission have galvanised opinion even more," one serving member of the Defence Forces said.
The journal Industrial Relation News (IRN) reported that the PSPC was recommending a 10% increase in the Military Service Allowance (MSA).
This caused anger among the Defence Forces rank-and-file, as it worked out at an increase of just 96c a day before tax.